Google: It's Easier To Tell If A Page Is Slow Vs. Fast

Paul Bakaus, one of the more well-known faces behind Google's AMP project, said a while back on Twitter that it is easier to tell if a page is slow versus telling if a page is fast. He said this after he said that the "whole area" of page speed "is technically very challenging."

In fact, someone quoted him as saying Google is not able to tell if a page is slow, which he did not deny saying:

Google's page speed tool does try to determine page speed and in fact, Google has labeled pages as being too slow in the past. But that didn't last. I guess Google can tell if a page is way too slow and act on that, anything more might be too hard.